Well, it's been a few days trying to do this properly, but i got no idea on how to do it :s

I got a situation where you go down infinitely, bouncing on platforms, and i need a background to wrap around the screen, but following the player. Think of those space shooters, but im moving back and forth instead of going always in the same direction.

I've actually got it to work, by stretching a tiled background to the ScrollYBottom and using the scroll x rate things, but well, since the game is kinda infinite, the thing can get pretty huge. While this works, it's not really useful since i cant put stuff like particles and sprites on that layer, and even though it didn't happen yet, i expect things to explode when the tiled background reaches something like 9999999 heigh XD

You can make use of Daiz's Flood Shooter, it has an infinitely scrolling background among other useful things. The trick is to use the texture offsetting feature to make an illusion of a moving background.